Head lamp



HEAD LAMP Filed Dec. 31, 1924 2 Sheets-Sheet l March 5, 1929; F, ENGLE llflfifi 657 HEAD LAMP Filed Dec. 31, 1924 2 Sheets-Sheet 2 atented err rare learnt FEES FRANK G. ENGLE, OF NEW YORK, N. Y.

HEAD LAMP.

Application filed December 31, 1924. Serial No. 759,184.

vance of an automobile may be properly illuminated and other portions left in darkness, thus, for example, eliminating the glare from the eyes of a driver of an approaching automobile on the opposite side of the roadway to that being traversed by the car carrying the invention.

In the accompanying drawings Figure 1 is a horizontal sectional view somewhat diagrammatic in its character through a head-lamp embodying the invention,

Figure 2 is a front elevation of the lamp,

Figure 3 illustrates a screen as illuminated by the structures shown in Figures 1 and 2,

Figure 4 is a front elevation of a modified form of lamp, I

Figure 5 is a view of a screen as illuminated by said lamp,

Figure 6 is a diagram of the circuits employed for the lamp, of Figure 4,

Figure 7 is a view in front elevation of a lamp with a slightly modified form of illuminating filament,

Figure 8 is a View of a screen showing the field70f illumination from the lamp of Figure Figure 9 is a diagram of the electrical circuits employed for the lamp of Figure 7.

Considering first the embodiment illustrated in Figures 1, 2 and 3, a parabolic refleet-or 10 is employed. this reflector terminating at the focal plane indicated at 11. The focal point, designated 12,. as is wellknown, is located at a distance from the vertex 13 equal to one-fourth of the diameter of the focal plane 11.

An electric lamp 14 is mounted in a socket member designated 15, and is preferably adjustable therein toward and from the reflector 10 in any well-known or desired manner. This lamp is provided with an illuminating element in the form of an incandescing filament 16. By referring to Figure 2, it will be noted that this filament constitutes a segment of a circle concentric to the focal point 12 and in the particular embodiment illustrated subtends an angle at said focal point of substantially 270 degrees. By re- 55 ferring to Figure 1, it will be noted that this filament ,is located in the focal plane. This the vehicle will be illuminated to a relatively position is of course, obtained by suitable tldJllStIIlOIlt; of the bulb if necessary.-

lVith this construction, if the lamp is operated, a path of light will be created, as shown substantially in Figure 3, this path of light comprising three-quarters of a circle,

designated 17, leaving one-fourth, 18, of said circle unilluminated. Assuming therefore that the lamp is on an automobile and a person is behind it looking in the direction in which the rays of light are emitted, it will be obvious by reference to Figure 3 that the right-hand side of the path in advance of great height, while the left-hand portion of the roadway will be illuminated, but that the'rays of light are cut off at a low level, thus avoiding the casting of a glaring beam of light into the eyes of persons approaching on the left-hand side of the roadway. The character of the beam of light is due to the parabolic reflector that terminates at the focal plane and the location of the filament substantially in said plane, but having no part at all coincident with the focal point.

-The formof the filament may be changed to secure different forms of illumination. Thus in Figures 4, 5 and 6, the reflector is designated 19 and the lamp 20. The focal point is shown at 21. .Extending around this focal pointis a filament comprising two sections 22 and 23, the section 22 corresponding to that designated 16in Figures 1 and 2, and is in a corresponding location. namely concentric to the focal point 21. and in the focal plane. The section 23 on the other hand is illustrated as eccentric to the focal point 21, but is in the focal plane. The filament therefore completely surrounds the focal point, but obviously the two free terminals of the sections 22 and 23 are spaced apart, as shown. Preferably means are provided for separately supplying'current to the two sections. Thus in Figure 6 a source of current is indicated at 24, and one pole has a connection 25 with the outer terminal of one of the sections as 22. Two leads 26 extend respectively to the outer terminal of the other section 23 and to a common connection between the two sections 22 and 23. A switch 27 electrically connected to the opposite pole of the source of electrical energy 24 has two arms adapted to alternately contact with the leads 26. With this arrangement it will be evident that if the 10 switch 27 is swung into contact with the lefthand lead 26, current will pass through both filament sections 22 and 23, while if swung to the right the section 23 will be cut off and the current will pass solely through the section 22. I

When the entire filaments 2223 is in incandescent condition, the field of light delivered from the lamp will be substantially that illustrated in Figure 5, the area of the illumination from the filament section 22 being designated 28, and that from the filament section 23 being designated 29. When therefore the entire filament is operative a relatively broad beam of light is thrown, but the portion 23 may be made inoperative, as above described, thus destroying the section 29 of the beam, and leaving the illumination the same as that illustrated in Figure 3.

In the structure shown in Figures 7, 8 and 9, the reflector is designated 30, and the bulb 31. The filament in this instance comprises sections 32 and 33, said sections forming a substantially heart-shaped figure, and having a common intermediate terminal 34 and spaced free terminals 35 and 36. It will be understood that the filament surrounds the focal point 37, and is located in the focal plane, as with the first embodiment above described.

. The two sections 32 and 33 are operable in the same manner as the sections22 and 23 of the modification illustrated in Figures 4 and 6. That is to say, a battery or' other source of electrical energy 38 has a connection 39 with the terminal 36, and leads 42 are connected to the two terminals 3a and 35 respectively. A switch 41 operates to connect the battery 38 with either connection 42, thus throwing the current through the entire filament 32-33 or through the section 32 only.

When both filaments are in operation, a field of light is emitted from the lamp, substantially as illustrated in Figure 8, and comprises a section 43 produced by the filament section 32, and another section 44 produced by the filament section 33. This, it will be ob vious produces relatively high spaced illuminating fields 45 with a centrally depressed unilluminated portion 46. The consequence is that a roadway is illuminated in the central portion at a low level, but with increased brillancy because of the nearness of the portion of the filament which emits the light, to the focal point 37. As a consequence roadside obstructions and elevated signs are brought into the path of the light, but when a vehicle approaches, by cutting ofi the filament section 33 the field through which said vehicle passes, is left in darkness and thus glare in the approaching drivers eye is elimi nated.

From the foregoing it is thought that the construction, operation and many advantages of the herein described invention will be aparent to those skilled in the art, without urther description, and it will be understood that various changes in the size, shape, proportion and minor details of construction may be resorted to without departing from means for adjusting the position of the lamp vthe spirit or sacrificing any of the advantages angle at the said point with relation to the reflector to bring the said point to coincide with the focus and at the same time to bring the plane of the filament to coincide with the focal plane of the reflector.

2'. In a head lamp, the combination with a reflector of substantially parabolic form terminating forwardly at substantially the focal plane of an electric lamp having an 11- luminating filament located substantially in the focal lane out of the focal point and extending 1n substantially circular form 'approximately 270 degrees around said point.

3. In a head lamp, the combination with a reflector of substantially parabolic form terminatin forwardly at substantially the focal plane, 0 an electric lamp having an illuminating filament having an extended length located substantially in the focal plane out of the focal point and extending about the focal point, a portion of said filament so lying in the focal plane being substantially concentric to the focal point and another portion eccentric thereto. v

4. In a head lamp, the combination with a reflector of substantially parabolic form terminating forwardly at substantially the of an electric lamp having an illuminating length located substantially in the focal plane out of the focal point and about the focal point, a'portion of said filament so lying in the focal plane being substantially eccentric to the focal point and another portion concentric thereto, and means for independently causing the different sections to become luminous.

In testimony whereof, I affix my signature.

FRANK G. ENGLE. 

